129 lines
4.2 KiB
C
129 lines
4.2 KiB
C
/****************************************************************************
|
|
* arch/arm/src/samd2l2/sam_timerisr.c
|
|
*
|
|
* Licensed to the Apache Software Foundation (ASF) under one or more
|
|
* contributor license agreements. See the NOTICE file distributed with
|
|
* this work for additional information regarding copyright ownership. The
|
|
* ASF licenses this file to you under the Apache License, Version 2.0 (the
|
|
* "License"); you may not use this file except in compliance with the
|
|
* License. You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
|
* License for the specific language governing permissions and limitations
|
|
* under the License.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#include <nuttx/config.h>
|
|
|
|
#include <stdint.h>
|
|
#include <time.h>
|
|
#include <debug.h>
|
|
#include <nuttx/arch.h>
|
|
#include <arch/board/board.h>
|
|
|
|
#include "nvic.h"
|
|
#include "clock/clock.h"
|
|
#include "arm_internal.h"
|
|
#include "chip.h"
|
|
|
|
/****************************************************************************
|
|
* Pre-processor Definitions
|
|
****************************************************************************/
|
|
|
|
/* The desired timer interrupt frequency is provided by the definition
|
|
* CLK_TCK (see include/time.h). CLK_TCK defines the desired number of
|
|
* system clock ticks per second. That value is a user configurable setting
|
|
* that defaults to 100 (100 ticks per second = 10 MS interval).
|
|
*
|
|
* Then, for example, if the CPU clock is the SysTick and
|
|
* BOARD_CPU_FREQUENCY is 48MHz and CLK_TCK is 100, then the reload value
|
|
* would be:
|
|
*
|
|
* SYSTICK_RELOAD = (48,000,000 / 100) - 1
|
|
* = 479,999
|
|
* = 0x752ff
|
|
*
|
|
* Which fits within the maximum 24-bit reload value.
|
|
*/
|
|
|
|
#define SYSTICK_RELOAD ((BOARD_CPU_FREQUENCY / CLK_TCK) - 1)
|
|
|
|
/* The size of the reload field is 24 bits. Verify that the reload value
|
|
* will fit in the reload register.
|
|
*/
|
|
|
|
#if SYSTICK_RELOAD > 0x00ffffff
|
|
# error SYSTICK_RELOAD exceeds the range of the RELOAD register
|
|
#endif
|
|
|
|
/****************************************************************************
|
|
* Private Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Function: sam_timerisr
|
|
*
|
|
* Description:
|
|
* The timer ISR will perform a variety of services for various portions
|
|
* of the systems.
|
|
*
|
|
****************************************************************************/
|
|
|
|
static int sam_timerisr(int irq, uint32_t *regs, void *arg)
|
|
{
|
|
/* Process timer interrupt */
|
|
|
|
nxsched_process_timer();
|
|
return 0;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Function: up_timer_initialize
|
|
*
|
|
* Description:
|
|
* This function is called during start-up to initialize
|
|
* the timer interrupt.
|
|
*
|
|
****************************************************************************/
|
|
|
|
void up_timer_initialize(void)
|
|
{
|
|
uint32_t regval;
|
|
|
|
/* Set the SysTick interrupt to the default priority */
|
|
|
|
regval = getreg32(ARMV6M_SYSCON_SHPR3);
|
|
regval &= ~SYSCON_SHPR3_PRI_15_MASK;
|
|
regval |= (NVIC_SYSH_PRIORITY_DEFAULT << SYSCON_SHPR3_PRI_15_SHIFT);
|
|
putreg32(regval, ARMV6M_SYSCON_SHPR3);
|
|
|
|
/* Configure SysTick to interrupt at the requested rate */
|
|
|
|
putreg32(SYSTICK_RELOAD, ARMV6M_SYSTICK_RVR);
|
|
|
|
/* Attach the timer interrupt vector */
|
|
|
|
irq_attach(SAM_IRQ_SYSTICK, (xcpt_t)sam_timerisr, NULL);
|
|
|
|
/* Enable SysTick interrupts */
|
|
|
|
putreg32((SYSTICK_CSR_TICKINT | SYSTICK_CSR_ENABLE), ARMV6M_SYSTICK_CSR);
|
|
|
|
/* And enable the timer interrupt */
|
|
|
|
up_enable_irq(SAM_IRQ_SYSTICK);
|
|
}
|